How to add a driver to body text
After adding a text object, finding out the name of the associated property ("body") and selecting it...

&gt;&gt;&gt; C.scene.objects.active.data.driver_add("body")
Traceback (most recent call last):
  File "&lt;blender_console&gt;", line 1, in &lt;module&gt;
TypeError: bpy_struct.driver_add(): property "body" not animatable


That is, I tried to add a driver to it from the python console. It doesn't seem to be possible, sorry. Depending on what exactly you want to put in the text object, using multiple objects might be an option?